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Drone-wrecking laser gun to sail on US warship

By Paul Marks

Video: Laser weapon tested

Incinerating a million dollars’ worth of equipment in 3 seconds flat is pretty easy if you’re the US navy and you need to destroy a hostile drone&colon; short-range interceptor missiles that will do the job cost up to &dollar;1.4 million. But when the USS Ponce steams into the Arabian Gulf next year, it will have a far less costly countermeasure at its disposal&colon; it will be the first warship to be armed with a shipboard laser weapon, the US Office of Naval Research has revealed.

Developed by Raytheon Missile Systems, based in Tucson, Arizona, the Laser Weapon System (LaWS) will be able to track and destroy drones or explosives-packed speedboats like the one which attacked the USS Cole in Yemen in 2000, killing 17 sailors. It does so with a searing beam of infrared radiation from a 100-kilowatt fibre-optic laser – and each firing costs just a few dollars in electricity. What’s more, the system can track agile targets that quickly change direction, and of course its beams travel at the speed of light. And whereas missile systems need to be reloaded for reuse, a laser can be fired repeatedly so long as the ship has enough power and the weapon can be adequately cooled between shots.

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Although the first such system cost &dollar;32 million, in the longer run it will be “tremendously affordable”, says US navy research chief Matthew Klunder. The laser has so far excelled in tests, successfully combusting drones and setting speedboat outboard motors alight.

It’s no accident that the first laser weapon will be deployed on a ship, says Elizabeth Quintana, a defence systems analyst at the Royal United Services Institute in London. All branches of the US military have experimented with lasers, but those based on chemical lasers such as the Airborne Laser , an aircraft-mounted antiballistic missile weapon, and the Tactical High Energy Laser, which targets artillery rockets, were abandoned partly because of the huge power supply needed – one that required six trucks to transport, in the case of the THEL. “But a modern warship is able to generate a lot of electricity, more than enough to power a laser weapon,” she says.

Weather challenge

The LaWS deployment is itself a test, however&colon; many technical issues still need ironing out, as a report to the US congress detailed on 14 March . One important challenge is to make the system cope better with atmospheric phenomena like fog, rain, and airborne sand and dust, which can slash the infrared laser beam’s power and range. “Weather is an issue for any optical weapons system,” says Don Linnell, a director of L-3 Integrated Optical Systems of Pittsburgh, Pennsylvania, which makes the precision beam-steering mirror set-up that lets LaWS work on a rolling, pitching ship deck. “The environmental impacts on the laser system have been characterised and our efforts continue in this area.” Changes can be made to the laser’s wavelength to adapt to the weather to make it less likely to be absorbed. Adaptive optics can be used to counteract the effects of atmospheric turbulence, too.

Another unknown is safety&colon; a beam that misses its target could hit friendly vessels, aircraft or satellites. “The safety aspects of firing a laser, knowing what is behind the target and the rules of engagement for this new type of weapon continue to evolve,” says Linnell.

Counter-countermeasures are bound to be in the works. “The US is already looking at the possible countermeasures its lasers will meet – like drones and boats with very shiny, laser-reflecting surfaces or novel heat-absorbing materials that dissipate heat very quickly,” says Quintana.

But she expects lasers to deter attacks. “Knowing a ship has a laser has a strong psychological effect. It’s the stuff of Star Wars. Adversaries won’t want to try their drone’s luck against a laser.”